[Michael] Johnson's reaction time, [Peter Hürzeler of OMEGA] said, "was 440 thousandths of a second. Normally athletes leave between 130 and 140 thousandths of a second. ... I asked him, why did you have such a bad starting time?" Turned out, Johnson was in the ninth position, and the sound of the gun was reaching him too slowly.

Four tenths of a second is a massive amount of time in a sprint. Which sounds even crazier when you realise that it's caused by the amount of time it takes the bang to go from a gun to an athlete's ears, 20m away on the starting blocks. [The Atlantic]